1. Field of the Invention
The present invention relates to an electric vehicle, such as an in-wheel motor vehicle, that is equipped with motor(s) to drive wheels and that may be battery-powered or fuel cell-powered.
2. Description of Related Art
An electric vehicle may experience degradation in performance or malfunctions of a motor serving as a drive for the vehicle, a reducer for producing reduced rotation from the motor, and/or a wheel bearing. This can significantly affect the travel performance or travel safety. Reliability of these components is an urgent concern for an in-wheel motor drive system which, due to its smaller size, involves rapid rotation of a reducer and a motor.
To ensure such reliability, an in-wheel motor drive system has been proposed in which the temperature of components such as a wheel bearing, a reducer and a motor may be measured and monitored for overload, with features to limit a drive current in the motor or a rotational frequency of the motor according to the temperature measurements (see the Patent Document 1 listed below).    [Patent Document 1] JP Laid-open Patent Publication No. 2008-168790